Electrical connector



l959 J. B. LESCARBOURA 3, 64,055

ELECTRI CAL CONNECTOR Filed June 19, 1967 2 Sheets-Sheet 1 Egi co l Rgs I I g a I I 2 6 46 n lg I!! 17 INVENTOR Jean Bop liste LESCARBOURA g- 1969 J. B. LESCARBOURA v 3,464,055`

ELECTRI CAL CONNECTOR Filed June 19, 1967 2 Sheets-Sheet 2 Fig. Fig.8

I I I I'J 250 L l 27 27 I i INVENTOR Joun Bup ?isto LESCARBOURA ATTORNEY United States Patent O U.S. Ci. 339-204 Claims ABSTRACT OF THE DISCLOSURE An electrical connector comprising a block in which the direction of insertion of the conductor or lead to be clamped makes an acute angle with the axis of the clamping screw. The block is split and is provided with longitudinal threaded portions on the inner faces of the split for guiding the clamping screw while the bottom of the block fiares out in the direction of insertion of the conductor. A clamping stirrup is nonrotatably mounted on the clamping screw to be moved therewith and has an inclined portion facing the aforesaid flaring bottom; the conductor to be clamped between the said flaring portion and the movable stirrup inclined portion.

The present invention relates to improved electrical connectors.

More specifically, the invention rela-tes to connectors forming a screw-clamping terminal into which the direction of insertion of the conductor is close to a parallel to the axis of the screw. Usually, many electrical connectors comprise a metal block that is split or formed with a transverse housing into which the connector to be clamped is inserted whereas a screw normal to the direction of insertion of the conductor presses a stirrup over it. In view of the trend toward miniaturization of electrical apparatuses, this arrangement is often too cumbersome because of the necessity to provide, in the connecting assembly receiving the conductors, two inlets that are normal to one another, one for the reception of the screwdriver and the other one for the conductor to be connected.

To overcome this inconvenience, connectors have been proposed that use a clamping wedge, having a small slope, provided with a through screw driving the wedge in the housing and causing a lateral clamping efiect on the conductor between one of the two sides of the wedge and a corresponding wall of the housing. In such connectors, the wedge is a small metal body and the screw, that extends through it, threads into a screw-tapping formed at the bottom of the Connector housing. This particular Construction in which a metal body slides into another one requires accurate machining. In the case of a small connector, the screw-tapping located at the bottom of the housing is not easy to make. Nor is it easy, during assembly, to insert the wedge` with its screw. It has also been proposed to replace the clamping Wedge by a generally arcuate fiexible blade pressed against the base of the housing by the head of the screw. However, the clamping force of the blade over the conductor is then weak as compared to the locking force applied on the screw and the conductor is not locked over the full available length of a planar surface.

An object of the inventon is to overcome these drawbacks by providing a connecting device comprising a block in which the direction of insertion of the conductor to be clamped makes an acute angle with the axis of the clamping screw, the said device being characterized in that the block is formed with a housing having two parallel inner walls provided with screw-tappings facing one another, the said housing further having, for the clamping, a third inner wall inclined in relation to the axis of the screw-tappings whereas .a screw engages between the screw-tappings while driving between its head and its tip a bent metal strip having a clamping portion corresponding and parallel to the inclined inner wall of the block.

According to a preferred embodiment of the invention,

the connector block is slit longitudinally in facing relationship inwardly of each of the legs whereas the bottom of the slit rises obliquely in the direction of the length in relation to the tapping axis.

According to another embodiment of the invention, more specifically intended for the joint of an electric switch, the Connector block, shaped as a narroW U, is inserted into the housing of the molded material of the body of this switch, the said housing being further formed with two inlets making an angle of approximately 30, one for the insertion of the screwdriver and the other for the insertion of the conductor to be joined. Preferably, the two aforementioned inlets are separated by a wall defining a stopping abutment for the metal strip or pressing stirrup that are driven by the screw.

According to a still further embodiment of the invention, the said block is a prismatic case having two parallel inner walls, the third inner wall joining the two parallel walls and a fourth wall facing the third one, the two parallel inner walls each having `a bearing or holding portion directed toward the third wall which comprises a screw-tapping portion facing inwardly of the housing, the said bearing and tapping portions concentrically defining the insertion and clamping means for the screw in the case and the screw driving between its head and its tip a handle-shaped metal strip sliding in the case, this handle comprising a clamping portion defining a wedge in relation to the axis of the screw, the said clamping portion facing the fourth inner wall of the case which conforms with this wedge.

In an embodiment in accordance with the aforedescribed means, the connecter case is made of a stamped metal sheet, bent and shaped in such a manner as to form a prismatic funnel opened at both ends. The case has two parallel inner walls and a third inner wall normal to the two parallel walls, the said three walls defining the axis of the screw by their bearing and screw-tapping portions whereas the fourth wall widens or flares out in relation to this axis to provide for the insertion of the conductor and its Wedge-clarnping by the stirrup. The bent and joined ends making up the fourth wall are preferably provided with fastening means. Any other means such as welding may also be used.

Further features and advantages of the present invention will become apparent from the following description, given by way of example and having reference to the appended drawings wherein:

FIGURE l is an exploded view in elevation of the three essential parts of the connector, the block being shown in longitudinal cross-section;

FIGURE 2 is a side view of an assembled connector;

FIGURE 3 is a front view of the connector, the block being shown in longitudinal cross-section;

FIGURE 4 is a cross-sectional view taken along line IV-IV of FIGURE 3;

FIGURE 5 is a longitudinal cross-sectional view of an assembly of two connectors located in the joint of a switch or the like;

FIGURE 6 is a View in elevation, with the case shown in longitudinal cross-section, of a second embodiment of the invention and taken along line VI--VI of FIG- URE 8;

FIGURE 7 is a top view of the embodiment of FIG- URE 6;

FIGURE 8 is a side elevation View of the connector of FIGURE 6; and

FIGURE 9 is a plan View of a sheet metal blank cut out to form the case in the embodiment of FIGURE 6.

The embodiment illustrated in FIGURES 1 to 4 essentially comprises three parts; a screw 1 having a head la, a clearance neck lb and a pointed tip lc, a clamping stirrup 2 made of a bent and cut metal strip, a Connector block 3 slit in the form of a U as seen in FIGURE 4.

The clamping stirrup 2 comprises a collar 4 which may be first formed of two open half parts and thereafter press-closed around the neck lb of the screw. Following collar 4 is an inclined branch 5 then another branch 6 inclined in opposite direction and finally a heel 6a, the distance between collar 4 and heel 6a being such as to correspond to the distance between the neck 1b and the conical or pointed tip 1c of the screw. The assembly of screw 1 and stirrup 2 is of a width appropriate to allow sliding thereof in the slt 7 of block 3, the branches 8 of which on their inner walls 8a and Sb are formed with screw-tappings 9a and 9b. The branches of the block are connected at the rear by an inclined wall 10 making, with the axis of the screw-tappings, an angle a which can for instance be 30. The branch 6 of the stirrup 2 must be formed to have this same angle a. Branches 5 and 6 are of rectangular cross-section whereby to smoothly slide in the slit 7, the heel 6 similarly sliding in the said slt forwardly of the screw-tappings.

The bottom of the slt 7 and the branch 6 of the clamping stirrup thus define a clamping chamber 7a (see FIG- 'URE 4).

It is in this chamber, making an acute angle with the axis of the clamping screw, that a pair of conductors 21, 22 can be clamped together by inserting them through face 11 or face 12, at will.

FIGURE 5 illustrates the use of a connecter, according to the invention, in the molded joint base of a switch. It is obvious that this joint base may form part of any electric apparatus such as an electric plug, a transformer, a circuit breaker, etc. and that is why the apparatus is not shown in full. The joint base made of insulating mate-` rial may compn'se, in any known manner, many parts with joints in such a manner as to constitute cavities in which the connector blocks of the invention are housed. For instance, the base may be formed of two symmetrical molded parts connected by screws extending through holes 14.

The block 3 is held in its cavity by the shoulder 16, the molded parts defining three passages 17, 18 and 19 used as follows: passage 17 for the insertion of the conductor to be connected, making an angle of 30 with the axis of the screw; passage 19 for a junction bar 21 of the internal connection of the apparatus. The bar 21 is advantageously provided with indentations 21a on the face thereof that is to bear against the conductor. The passage 18 is for the insertion of a screwdriver. It is seen that the partition separating passages 17 and 18 is intended to serve as abutrnent 20a for the branch 5 of the clamping stirrup. Thus, the screw may not be unthreaded beyond its tapped portion and be lost. The cavities of the connection base further comprise a cutout 13 to allow complete closure of the clamping stirrup.

It will be easily understood that the invention is not to be limited to the aforedescribed embodments. It comprises all forms of block 3 to be used in connections of various types. Thus, in the case of power conductors having a certain rigidity, the abutment 20a will be removed and the general support will also be slt outwardly in such a manner as to allow insertion of the conductor by introducing it through the slt, the screw and its clamping stirrup being removed and thereafter replaced. In a general manner, the invention applies to all connectors using the essential means above described.

The aforedescribed embodiment essentially comprises a block obtained from a body of molten metal in such a manner as to form a U-shaped fork, the two branches of the U containing a screw-tapping portion for the screw which is inserted between the branches, the bottom of the fork defining a surface inclined at an acute angle in relation to the axis of the screw.

a However, it is not industrially easy to obtain two screw-tapping poritons between the inner faces of a U- shaped part the branches of which tend to bend outwardly; It is possible to stamp a flat piece with the two screwtapping portions and to thereafter bend them but the accuracy of such an operation is dubious.

- Besides, in such a clamping stirru device sliding in a slit block, if clamping of the screw is too strong the branches may spread and the screw may slip out of the screw-tapping.

Referring to FIGURE 6, it is readily seen that the screw 1 provided with its clamping stirrup 5 is in the same clamping condition of the conductors 21, 22 as in the device of FIGURES 1 to 5. With reference to FIG- URE 7, it is seen that the screw 1 is centered, on the one hand, between the two reentrant surfaces 2411, 24b of the wall of body 30 enclosing the Connector and, on the other hand, a cylindrical surface 25 of the wall 29. This surface 25 is provided with a screw-tapping portion 25a. The portion 24a and its adjacent portion 26a are obtained by stamping of the wall 28a of the body 30.

FIGURES 6, 7 and 8 illustrate the general shape of the body of the connector which is that of a prismatic case having two parallel walls 28a and 28b, an upright wall 29 and an inclined wall 31, the latter forming a funnel and being parallel to the portion 6 of the stirrup. The inclined wall 31 comprises undulations 27 the purpose of which is to be explained hereinafter.

FIGURE 9 illustrates a cut metal sheet intended to form, by -bending, the stirrup shape of the body 30. The broken lines indicate the location of the bends to constitute the walls 29, 28a, 2811. The wall 31 opposite 29 is formed by two half flaps at the extremites of the sheet, the edges of which are cut out in the form of cooperating dovetails 32a, 33a, 32b and 33b. The latter provide the resisting fastening means that constitute the fourth wall of the stirrup. Besides, undulations 27 reinforce the wall 31' and mprove the fastening provided in its thckness.

Referring to FIGURES 6 and 7, it is seen that the bearing surfaces 24a, 2417 and the screw-tapping portion 25a allow centering and guiding of the screw. During clamping of the conductors 21, 22, the looking forces due to the wedge of the stirrup react between the wall 29 and its screw-tapping portion 25a and the inclined wall 31 which ssolidly fastened and reinforced by the undulations 27.

This embodiment of the Connector provides manufacturng conditions appropriate for mass production. It also offers improved clamping qualities. The improvement whch is the object of the instant invention is not limited to the particular embodiments described. Particularly, it would apply as well to a Connector body obtained by molding with variations in the shape useful for this type of Construction.

I claim:

1. A connecter for electrical conductors comprising:

(a) a block having a housing defining two opposed nner walls;

(b) slrew-tapped and guiding means on said opposed wa s;

(e) a screw threaded on said screw-tapped and guidng means to be axially moved when rotated;

(d) said housing further defining a conductor-clamping wall making an acute angle with the axis of said screw;

(e) a handle-shaped metal strip mounted on said screw to be displaced therewith in said housing when said screw moves axially subsequent to rotation;

(f) said metal strip including a clamping portion generally parallel to said clamping wall whereby to be displaced to and from said clamping wall as said screw is moved to clamp and unclamp a conductor between said clamping wall and said strip clamping portion;

(g) said screw having hearing portions and said metal strip being formed with bearings at the ends thereof in which the said screw hearing portions rotate.

2. A device according to claim 1, wherein:

said 'block is slit longitudinally in the form of a U in cross-section to constitute the said housing;

said screw-tapped and guiding means are constituted by screw-tapped portions facing one another on the lateral inner walls of said U;

the bottom of said U-shaped housing constitutes said conductor clamping wall and fiares outwardly away from said screw in the direction of insertion of the said screw.

3. A connecter as claimed in claim 1, wherein:

the said block is a prismatic case comprising two parallel inner walls constituting the said opposed walls and a third wall joining the said two parallel walls;

the said screw-tapped and guiding means are constituted by screw-retaining elements formed on the said two parallel walls and a screw-tapped portion formed on said third wall;

the said screw-retaining elements and screw-tapped portions concentrically determining the axis of insertion of said screw in said housing.

4. A device according to claim 3, wherein said case is formed of a metal sheet cut and bent in such a manner as to form a primatic funnel with a fourth face thereof flaring outwardly to constitute the said clamping wall.

5. A device according to claim 4, wherein said case is formed of a single metal sheet with said fourth wall defined by the extremities of said metal sheet and having closing edges provided with interlocking dovetail cut-outs.

6. A device according to claim 4, wherein said fourth wall is formed with reinforcing undulations.

7. A device according to claim 1, wherein the screw hearing portions are a clearance neck beneath the screw head and a conical tip at the end of the screw.

8. A device according to claim 7, wherein said metal strip bearing is in the form of a hook receivng said conical tip.

9. A device according to claim 7, wherein said metal strip is connected to said screw neck by an open collar set around said neck.

10. A Connector according to claim 1, including a hollowed out connecting base and means mounting said connector into said base; said base formed with an inlet pas- 'sage therethrough at the screw tip end; a connecting bar inserted through said inlet passage and lying against said clamping wall; said hollowed out base formed With two further inlet passages, one in the extension of said screw for the insertion of a screwdriver and the other in the extension of said clamping wall for the insertion of a conductor to be clamped.

References Cited UNITED STATES PATENTS 9l3,160 2/1909 Pride 339-174 l,857,398 5/1932 Phillips 339-270 X 1,926,927 9/1933 Woertz 175-369 2,193,691 3/1940` Johnson et al. 200-134 3,260,989 7/1966 Curtis 339-272 FOREIGN PATENTS 1,09l,168 10/1960 Germany.

778,286 7/ 1957 Great Britain.

U.S. Cl. X.R. 339-270 

